How to Reduce Array of Arrays in JavaScript Using Moment.js for Weekly Data Summation

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Introduction

The Problem

You are presented with a data structure that looks something like this:

[[See Video to Reveal this Text or Code Snippet]]

You want to aggregate this data into weekly totals, which means you should convert each date to the start of its week and then sum the values for all entries within the same week.

The Solution

Step 1: Use reduce() to Aggregate Data

We'll start by utilizing the JavaScript reduce() method to create an object that will hold the weekly sums. The code structure will look like this:

[[See Video to Reveal this Text or Code Snippet]]

In this script:

The reduce() method initializes an empty object.

For each item in data, it calculates the start of the week using moment().startOf("isoWeek") and sums up the corresponding values.

Step 2: Convert Object Back to Array

[[See Video to Reveal this Text or Code Snippet]]

This will provide you with an array that sums the totals by week, creating the final desired output.

Final Result

When you log finalOutput, you will get something like this:

[[See Video to Reveal this Text or Code Snippet]]

Output:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

For large data sets, this method typically performs better than nested loops, maintaining both speed and readability. Ready to give it a try? Happy coding!